Handling insert and delete with multiple users in SQL - sql

Question

I would like to maintain a system for uploading data through Excel to SQL Server with ADO method. The process consists of two steps:
the raw data is inserted to temporary table, say dbo.TableTemp
the raw data is processed with a stored procedure and inserted to a dbo.GoodTable
delete from dbo.TableTemp at the end of stored procedure
Is there any way to be sure that the activities of two users not overlap? For example the delete from dbo.TableTemp of user1 will not be executed after user2 inserts data and before the data are processed?
Update. Unluckily I have not been successful with #temp tables. They seem to be too much temporary and when I try to insert data into them #temps already do not exist. For uploading data I use the variation of code by Sergey Vaselenko downloaded from here: http://www.excel-sql-server.com/excel-sql-server-import-export-using-vba.htm#Excel Data Export to SQL Server using ADO
In the Sergey's solution it is possible to create table by stored procedure prior to inserting the data in step 1. But when I create #temp table with stored procedure, it vanishes at the end of procedure, so I cannot insert data to it. Any help please?

Answer 1

Use temporary tables #TableTemp. Those are specific for each session and thus would not overlap.
There are two types of temporary tables: local and global. They differ
from each other in their names, their visibility, and their
availability. Local temporary tables have a single number sign (#) as
the first character of their names; they are visible only to the
current connection for the user, and they are deleted when the user
disconnects from the instance of SQL Server. Global temporary tables
have two number signs (##) as the first characters of their names;
they are visible to any user after they are created, and they are
deleted when all users referencing the table disconnect from the
instance of SQL Server.
Update. Looks like this particular Excel-SQL Server Import-Export using VBA use separate functions to create table and upload the data each opening and closing own connection. From SQL Server perspective those functions operate in different sessions and thus temporary tables do not persist. I think this solution can be rewritten to use single connection to create temporary table, populate, process the data and output the results into permanent table.
You might also find useful this question: How do I make an ADODB.Connection Persistent in VBA in Excel? In particular - Kevin Pope's answer suggesting the use of global connection variable opened and closed with the workbook itself:
Global dbConnPublic As ADODB.Connection
In the "ThisWorkbook" object:
Private Sub Workbook_Open()
Set dbConnPublic = openDBConn() 'Or whatever your DB connection function is called
End Sub
Private Sub Workbook_BeforeClose(Cancel As Boolean)
dbConnPublic.Close
End Sub

Answer 2

Another approach - use TABLE variable. From MSDN
CREATE #AddedValues TABLE (ID INT, SomeValue VARCHAR(50))
Then use it normally as tables in the query.
INSERT INTO #AddedValues (ID, SomeValue) VALUES (1, 'Test');
SELECT ID FROM #AddedValues WHERE SomeValue = 'Test';
Table variable's scope limited to the batch. So you can be sure that other user or even same user will not access it from another batch.
From MSDN
A table variable behaves like a local variable. It has a well-defined
scope. This is the function, stored procedure, or batch that it is
declared in.

Answer 3

Instead of using a Temp-Table in the user database you can put it in the temp db. Prefix the tablename in a CREATE TABLE Statement with # to create it in tempdb.
For example
CREATE TABLE #TableTemp (....)
Only the session that creates the temp table has access to it and SQL Server deletes the table automatically.